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8. MAINTENANCE
8.1 SYSTEM STORAGE
Battery Life:
The MESTA UPS should be stored with the batteries fully charged and all breakers in the
off position. MESTA Battery Cabinets should also be stored with the batteries fully charged. Storage
temperature should be maintained between -20
°
C and 40
°
C. The life of the batteries may be greatly
reduced if stored at temperatures exceeding 30
°
C for extended periods of time. Optimal storage
temperature for maximum battery life is 20
°
C or lower. Also, batteries may be permanently damaged if
not removed from storage periodically and fully recharged at least once every 6 months. To recharge
batteries inside UPS, simply remove the UPS from storage and connect the unit to an AC power source
for a minimum of 4 hours (make sure batteries are being charged by monitoring the charge current and
battery charge percentage on Display#1 of the LCD screen. Then you may turn the unit off again and
return it to storage for up to another 6 months. To recharge batteries in a battery cabinet purchased
from Mesta, follow the directions to connect the battery cabinet to a Mesta UPS in Section 2 of this
manual. Allow a minimum of 4 hours charging per battery cabinet.
8.2 OPENING THE UPS CABINET
WARNING
Only qualified technicians or supervised personnel should open the UPS and only after ALL of the
following WARNINGS and instructions are read and fully understood. Otherwise, maintenance
personnel may be exposed to an electrical shock hazard that could result in death or injury, or
damage to the UPS or its electrical loads may occur.
WARNING
Risk of
Electric Shock
exists inside the UPS. The UPS receives power from the AC source (via
external wiring to the INPUT VOLTAGE terminal block) and a DC source (via the internal and/or
external batteries). Maintenance personnel must be aware of this hazard, or they may be exposed to
an electrical shock hazard that could result in death or injury, or damage to the UPS or its electrical
loads.
WARNING
The UPS internally contains capacitive components, which remain energized even after power to the
UPS has been turned off. After the UPS is turned off, the front panel LEDs and LCD display will go
off within 20 seconds. Under these circumstances the voltage across these capacitive components
will be minimized to safe levels within 1 minute of turning the UPS off. If, however, the LEDs never
come on when the UPS is turned on or never go off when the UPS is turned off, a problem exists with
the unit. Under such conditions it is possible for hazardous voltages to remain for longer periods of
time. If such a malfunction exists, it is advisable not to open the unit. Instead, contact the
manufacturer or nearest repair center. A qualified technician will need to check the DC voltage
across the buss bars that connect the large capacitors attached to the heat sink before proceeding
with any internal maintenance. This voltage could be as high as 250 volts DC. One should wait until
voltage is below 30 volts DC before proceeding. Otherwise, maintenance personnel may be exposed
to an electrical shock hazard that could result in death or injury.
